Process of making basic zinc formaldehyde hydrosulfite, (s.)



UNITED srA'rEs PATENT oE r o EMILE A. FOURNEAUX, 01? NEW YORIQN. Y.,"ASSIGNOR To HERMAN A.

- MErZ, OF NEW YORK, N. Y.

PROCESS OF MAKlNG BASIC ZINC FORMALDEHYDE HYDROSULFITE, (3.)

Specification of Letters Patent.

Patented March 6, 1906.

Application filed July 14, 1905. Serial No, 269,721-

To all whom may concern.-

Be it known that I, EMILE A. FOURNEAUX,

' a citizen of the United States, residing at 122 Hudson street, New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Processes of Making Basic Zinc Formaldehyde Hydrcsu ifite, (8,) of which the fol-- Znso,-.oH,o.H,o, occurring as a white crystalline precipitate.

This compoundis relatively stable, being capable of drying without decomposition upon the water-bath' in open air, and possesses a high reducing power, one part being able to reduce about one and one-half parts of pure indigo in the form of indigo sulfonic acid. In said application I have also described and claimed a process of making this basic zinc compound, said process consistin in treating zinc hydrosulfite with formalde yde and a suitable alkaline compound, as sodium carbonate, the basic zinc salt being apparently formed in accordance with the equation:

' exam In my app1ication,Serial No. 259,469,filed May 8, 1905, I have described and claimed another process by which the above-described zinc compound may be produced, said process consisting, essentially, in mixing an alkali formaldehydebisulfite with zinc and su plying a suitable acid at such rate that the presence of free acid is substantiallyavoided, an le of the process being expressed by the fo owing equation:

basic zinc formaldehyde hydrosulfite (S) can be produced in a state of substantial purity and unaccompanied by any by-product by reducing an aqueous solution containing sulfurous acid and formaldehyde, preferably in equimolecular amounts with zinc-dust, the reaction probably occurring in accordance with the equation:

The following conditions have been found to give satisfactory results: To a concentrated solution containing one molecular proportion of sulfurous acid and one molecular proportion of formaldehyde add a little more than one molecular proportion of zinc-dust,

then heat to a temperature exceeding centigrade, and preferably almost to boiling, while stirring constantl The insoluble basic zinc formaldehyde hy rosulfite (S) separates in crystalline form. When the reaction is terminated,.it is filtered, washed, and dried.

Instead of acting with Zinc-dust upon a solution containin sulfurousacid and formaldehyde it is aso feasible to act with two molecular proportions of sulfurous acid upon one molecular proportion of zinc-dust in aqueous suspension, thus producing zinc hydrosulfite, (ZnS O,,)then add two molecular proportions of. formaldehyde, then after the reaction has taken place one molecular proportion of zinc-dust, and heat while constantly stirring, as described above.

I claim- 1. The process of making basic zinc formaldehyde hydrosulfite (S) which consists in reacting with zinc on sulfurous acid and formaldehyde in solution; substantially as described. Y

2. The process of making basic zinc for; maldehyde hydrosulfite (S) which consists in reacting with two molecular proportions of sulfurous acid on one molecular proportion of zinc, adding two molecular proportions of formaldehyde, and reducing the resulting solution with one molecular proportion of zinc substantially as described. I

In testimony whereof I affixnly signature in presence of two witnesses. I

p A. FOURNEAUX.

Witnesses:

H. S. NEIMAN, ALEXANDER ScHwAIisMAN. 

